How this toothbrush saved the International Space Station

Emma Woollacott, 6th September 2012

NASA astronauts successfully replaced a power switching unit on the International Space Station yesterday, using a $3 toothbrush to clean up a stuck bolt.

Last Thursday, NASA Flight Engineer Sunita Williams and Japan Aerospace Exploration Agency Flight Engineer Akihiko Hoshide were unable to install a new Main Bus Switching Unit (MBSU) on the ISS’s s-zero truss because of an accumulation of metal shavings around one of the bolts.

But in a six-hour spacewalk yesterday, they finished the job, after removing the shavings using an improvised tool. They blew away the worst of the debris with puffs of compressed nitrogen, then used the toothbrush to clean away the rest.

"Looks like you guys just fixed the station," astronaut Jack Fischer radioed from Mission Control at NASA's Johnson Space Center in Houston.

Without the MBSU, the station had been unable to relay power from two of its eight solar arrays. The problem was all the more serious because, on Saturday, a direct current switching unit failed because of a presumed short somewhere in the system, bringing a third solar array offline.

It left the station operating on just five of its eight power channels for the first time in years, forcing astronauts to manage their power supply very carefully.

"It's been like living on the set of 'Apollo 13' the past few days," said Fischer. "NASA does impossible pretty darn well, so congratulations to the whole team."